Electric fuse.



H. C. BRONSON.

ELECTRIC FUSE.

APPLICATION FILED ocT. 2s, 1914.

Patented Nov. 6, 1917.

UNITED sfrarns PATENT orrion.

RALPH C. BRONSON, 0F GHICAGO, ILLINOIS.

ELECTRIC FUSE.

so that whenl the fusible strip is blown out the hot metalwill not bescattered about and so that the fusible strip 'can easily, quickly andcheaply be replaced.

- Whenthe fuse strlp 1n plugs of this 'kind 'is blown there is developeda high pressure on the inside of thecasing and where there isv an outerrotating part for closmg the opening in the casing, this pressure isliable to disrupt or distort the casing, so as to prevent the furtheruse of the device, and one of the objects of my presentinvention 1s toprovide against the injury due to this pressure.

Electric fuse devices of this kind are used onswitchboards and are moreor -less diiiicult of access. If, in removing and renewing 'the fusemetal it is necessary to remove screws or other parts of the devicethese .screws or other parts are liable to be dropped and to therebybe'lost, or again picked up with difficulty, thus making such fusedevices commercially impracticable and very diiiicult to introduce intoany extensive use.

One of the -objects of my invention is to provide a fuse device where noscrews or other parts need be removed when renewing the fusible strip,the device, as itl were, be-

'- ingl a single structure having no parts which can drop down or belost during 'the process of renewing the fusible strip, and, at the sametime, provide a good electrical contact at the point where the fusemetal 1s attached to 1t so as to insure the proper action ofthe device,such contact arrangement not being af- Flgure 1 is a new showing themvenuqn view taken on line fected by the heat developed whenjthe fuse isblown. l 1 The .invention is illustratedin the 'accomg drawings,wherein, f

Fig'.V 2 is a sectional 2-2'of 13j e;

Specification of Letters Patent.

Patenteanov'. lc, 1917.

Application med October 23, 1914. Serial 110,868,233.

Fig. 3 is a sectional-view taken -on line v-ofligl; a cltlzen of theUnited States, residlng at 'Fig 1.

Fig.` 4 is a section taken yon. line 4-4 of Fig 5 is a view of one ofthe contact termlnals separate from the casing.

Like numerals refer 'to like parts throughout the several figures. Y

Referring now to drawings, I have shown an electric fuse of thecartridge type. This device comprises a casing 1 of non-conductingmaterlalv such as fiber or the like having two metallic end pieces 2.The casing 1, is made up of two parts, an outer cylindrical part 3 andan inner cylindrical part 4. The in ner part 4 is stationary and isconnected wlththe end pieces in any desired manner. The outer p art4 3is rotatably mounted so that it may be rotated. The inner part .4 isprovided with an elongated opening 5 and the outer'part 3 isalsoprovided with an elongated'opening 6. By turning the outer part 3 theopening 6 may be made to register with theopening 5 so as to permitaccess to llthe interior of the casing.l When the outer part 3 isrotated so as to move the opening 6 to one side o casing is then closed.The ends of the outer-cylindrical part 3 project under the metallic endpieces 2 so the opening 5, the A that said metallic end pieces areengaged'by the ends of the outer cylindrical part 5' so as to take thepressure due to the explosion inside the casing when the fuse blows. Itwill be seen that by this construction the metallic end pieces 2, sincethey overlap both the inner cylindrical part 4 and the outer cyliningthe outer cylindrical part substantially the same strength as the innerpart andpreventing the pressure due to the blowing of the fuse frombulging or otherwise distorting or inj uring the cylindrical parts.

`drical part 3, grip those parts thereby giv- It will be seen if theouter cylindrical part does noteXtend under the metallic end pieces, thepressure inside the 'casing will not be greatly resisted by the outercylindrical parts and the'distortion of the parts-- will, even-if itdoes not disrupt the cylindrical parts, prevent the outer part fromvbeing turned on the inner part to close the casing. Projectingthroughthe ends 2 of.

'the casing, are the contact terminals 7 The .inner ends'of theselcontact terminals are cut i @away so as to. forni the narrow neck 8 andthe enlarged inner end 9. A bent fastening piece is bent upon the neck 8so as to project between the enlarged end 9 and the main body of theterminal and the ends 11 thereof bent along the inner surface of thepart 4. Screws 12 pass through the caps and the part 4 of the casing andengage the ends of the fastening pieces 10 so as to hold the end pieces2 and the contact terminals the end pieces 14 of the 'fusible piece 15are placed under this contact so as to make a clamping electricalcontact between the fusible metal strip and the contact terminals y7.The end pieces 2 andthe outer partB and inner part 4 are slottedopposite these screws as shown in Fig. 1 so as to permit easy accessthereto. Then the outer part 3 is rotated so that the openings 5 and 6register,

- the slots therein also then register with the slots in the endpieces 2and the inner pieces 4 of the casing. l l

When the parts are assembled, the fusible metal strip is placed inposition by inserting the ends under the contact screws 13 and thentightening said screws so as to get the desired pressure to insure theproper electrical contact. The interior of the casing is then filledwith some non-conducting fireproof material such as powdered asbestosand the casing closed-by rotating the outer part 3.' When the fuse blowsit will be seen that it. is entirely inclosed and the explosionl isconfined within the casing. The end pieces 2 are preferably providedwith Ventilating openings 1 6. When the fuse is melted, it is onlynecessary to rotate the casing 3 so as to bring the opening 6 inposition to register with the opening 5. The powdered contents of thecasing may then be discharged and the screws 13 loosened by means of ascrew-driver and the ends of the fuse metal removed and a new piece offuse metal inserted. The casing is then again filled withpowdered'material and the outer part 3 rotated to close the opening. Itwill therefore be seen that by means of this co-nstruction the meltedfuse metal can be easily `and quickly replaced and the device used overand over again. The contact screws 13 are preferablyl arranged` so thatwhile they can be 'loosened they' cannot be completely removed. This canbe done by 11p-setting the end after the screws have been placed inposition. It will be seen that in this fuse there are no removable partswhich have to be removed to refill the fuse except the metal fuseitself, all other parts being fastened together so that they staytogether while'the new fuse metal is being put in place and hencenothing can be lost in this process to thereby interfere with the propelrefilling ofthe fuse.

I claim:

1. An electric fuse comprising a casing having an outer and innercylindrical partV of non-conducting material, the outer partbeingrotatably mounted upon the inner part, the two parts provided withopenings which are adapted to register when the parts are in apredetermined position so as to .give access to the casing, metal endpieces connected with said inner part and overlapping the outer part so'that the strength of the outer cylindrical part is utilized to resistthe expansion of the inner cylindrical part when the fuse is blown,without interfering with the turning movement of the outer cylindricalpart, contact terminals projectlng through said metal end pieces,terminal screws connected with the portions of said contact terminalsinside said casing, a fusible metal strip having end pieces adapted tobe inserted between the heads of said screws and said contact terminalsso that by screwing down the screws a good electrical contact can besecured, and slots in said outer and inner cylindrical parts, the slotsin the inner cylindrical parts eing opposite the heads of said screwsand the Slots 1n the outer cylindrical parts registering therewith whenthe openings in the two cylindrical parts register' whereby access tosaid screws is provided.

2. An electric fuse comprising a casing consisting of an innercylindrical part of non-conducting materialhaving an opening in the sidethereof through which the fuse metal is inserted, two metal end piecesconnected therewith one at each end thereof, contact terminalsprojecting through said end pieces into the interior of the casing andto which the fuse metal is connected, an outer cylindrical part shorterthan the inner part and rotatably mounted thereon, said outer parthaving an opening adapted to register with the o ening in the innercylindrical part when t e outer cylindrical part is moved to apredetermined position, said end pieces 'projecting part way along boththe inner and outer cylindrical parts and fixed against rotation withrelation to the inner cylindrical part and having a rotatable engagementwith the outer cylindrical part so that the Strength of the outercylindrical part is utilized to resist the ex ansion of the innercylindrical part when t e fuse is blown, without interfering withtheturning movement of the outer cylindrical part whereby bulging of theinner cylindrical part so as to interfere with the rotation of the outercylindrical part is prevented.

vdrieal part, the two cylindrical parts ing openings adapted to registerwhen they .are moved relatively to a preedetermined 3. An electric fusecomprising, a casingA having anouter and inner cylindrical part of'non-conducting material, the outer part being rotatably mounted upon theinner part, the two parts provided with openings which are adapted to'register when the parts are in a predetermined position so as to giveaccess to the fuse, metal end ieces projecting over the ends of Aboth osaid outer and inner cylindrical parts, so as to utilize the strength ofthe end pieces and the vouter cylindrical A'part in resisting theexpansion of the inner cylindrical part' due to the pressure producedWhen the fuse is blown, without interfering with the 'turning movementof the outer cylindrical part thus preventing the binding of the outercylindrical part, contact terminals connected with said metallic endpieces and` means for removably fastening a fusible metal strip to saidcontact terminals.

4. An electric fuse 'comprising a ycasing having an outer cylindricalpart and an in? ner cylindrical part, both made of non-conductingmaterial, the outer part being rota-v tably mounted upon the inner part,a re-` movable fuse contained in the inner c linposition so as to giveaccess to said inner cylindrical part, hollow end pieces into which theends of said inner cylindrical part.

project, screws passing through said end pieces and projecting into saidinner cylindrical part so as to fasten them together, said outercylindrical part being shorter drical than the inner'cylindrical partand having its .ends in vroximity to said screws so that they limit itslongitudinal movement, portions of said hollow end pieces projectingover the ends of said outer cylindrical part so as to permit it vtorotate but hold it'.

against outward distortion'when the fuse is blown. l

5. An electric fuse comprising a casing consisting of an inner clindrical part o non-conductmg materlal aving an openlng in the sidethereof through which the fuse metal is inserted,- two metal end pieceshaving overlapping portions projecting part way along the inner'cylindrical part, a part of the overlapping portion of each end pieceengaging the inner cylindrical part, there being a space between theinner cylindrical part and the remainder of the overlapping portion ofeach end piece, an outer cylindrical part of non-conducting materialrotatably mounted upon the inner cylindrical lpart and having reducedend portions which project into the spaces between the end pieces andthe inner cylindrical part, said outer cylindrical part having anopening adapted to register with the opening. in the inner cylindricalpart when the outer cylinpart is moved to a predetermined position.

In testimonywhereof, I affix my signature in the presence of twowitnesses this 3rd day of October 1914. RALPH C; BRONSON. Witnesses:

Bnssm S. RISE, MINNIE M. LINDENAU.

